TVI Resource Development (Phils.) Inc. (TVIRD) has gained a 60% indirect interest in the Mabilo Project (“Project”) through having acquired on January 31, 2022, all the outstanding capital stock of SageCapital Partners, Inc. (“SageCapital”). SageCapital is a holding company incorporated under the laws of the Philippines which, in turn, owns 60% of the outstanding capital stock of Mt.Labo Exploration and Development Corporation (“MLEDC”), a Philippines mining and minerals exploration development company whose projects are based in Camarines Norte, Philippines, and which is the owner and operator of the Mabilo Project (“Mabilo”).
RTG Mining Inc. (“RTG”) holds a 40% interest in MLEDC through SRM Gold.
TVI Pacific Inc. holds a 30.66% interest in TVI Resource Development Phils., Inc.
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Summary:
The Mabilo Property hosts mineralization of copper-gold-magnetite skarn type. Skarn describes a rock dominated by calc-silicate or calcium-magnesium silicate minerals formed by metasomatic replacement of carbonate-bearing rocks rich in calcium and magnesium. Skarn forms as a result of interaction of carbonate-bearing host rock with hydrothermal fluids derived from an igneous intrusion.
Skarn copper-gold-magnetite is considered to be the primary target at the Mabilo Property. While the occurrence of copper-gold-magnetite skarn may suggest some potential for porphyry copper-gold mineralization, no indication of this type of mineralization has been encountered and no porphyritic intrusions have been identified. There may also be potential for epithermal gold mineralization, but this is also a secondary target; pyrite-quartz overprint of the known skarn is of epithermal style, but is not known to be gold-mineralized.
Quaternary lahar and tuff deposits of the Labo Volcanics cover the southern and eastern two-thirds of the Mabilo exploration license, thickening southward from Venida. In the deposit area, the Labo Volcanics vary from about 30 m to 50 m in thickness, reflecting both palaeotopography and stratigraphic thickness. As a result of the poor exposure, younger volcanic cover and limited drilling, the geology of the older rocks in the license area is not well constrained.
Beneath the Labo volcanic unconformity, Tumbaga Formation sediments and volcanic sediments are intruded by a quartz diorite stock. The sediments include variably calcareous siltstones, volcanogenic sandstone and wacke, clean limestone, and silty limestone. The quartz diorite intrusion that has been drilled under cover at Mabilo is probably equivalent to the diorite intrusion mapped immediately north of the license which is assigned to the late Miocene Tamisan Diorite suite. The sedimentary lithologies are hornfelsed and metasomatically altered in the contact zone of the intrusion. The extensive hornfels and the irregular extent of the diorite are suggestive of a roof zone of a mid-level intrusion.
In the area of the resource, the bedrock geology dips moderately to steeply to the southwest (typically 50 - 60 degrees). A robust lithostratigraphy has not been defined and original rock-types can be obscured by alteration and mineralization overprint. However, the main magnetite skarn is interpreted to replace a massive clean limestone unit that has been metamorphosed to marble in the contact aureole of the quartz diorite intrusion. The thickness of the unit is variable, from 15 - 20 m in the southern part of the South Mineralized Zone (SMZ) and up to 50 - 80 m in the North Mineralized Zone (NMZ). This is interpreted to reflect primary sedimentary thickness variation and lateral facies variation. The overlying stratigraphy includes variably calcareous siltstone and mudstone, minor argillaceous limestone replaced by skarn, and subordinate volcaniclastic wacke horizons. The underlying stratigraphy includes similar calcareous siltstone and mudstone with limestone units (or skarn), notably a cherty limestone in the north, all underlain by a thick volcanic sandstone.
The clastic sediments have been metamorphosed to biotite hornfels and the calcareous and dolomitic siltstone and mudstone have been metamorphosed to calc-silicate or magnesian silicate hornfels in the contact aureole of the quartz diorite.
The mineralized bodies occur on the eastern contact of the quartz diorite stock that has been intersected in several drillholes. The magnetic data suggest that the stock is at least 1 km in diameter and forms the magnetic low with the north magnetic anomaly, southeast magnetic anomaly, and NMZ and SMZ at its margins. Where drilled, the quartz diorite is relatively unaltered with hornblende partly altered to chlorite and weak feldspar retrogressive alteration. On the northeast margin of the SMZ, strongly altered porphyritic intrusive rock has been intersected in drilling. They have been interpreted as dykes in the contact zone of the main stock.
The SMZ and NMZ are cut by a significant northwest-trending northeast dipping normal fault with a throw of not more than 10 m. The NMZ is interpreted to be fault-offset from the SMZ along a later northeast- trending, probably steeply dipping, dextral fault. The Venida skarn body probably represents a further fault offset along a similar northeast-trending fault.
A number of magnetite skarn occurrences are known within the Tumbaga Formation north of the Mabilo block and north of the Labo Volcanic cover, including Binit, B1 and Mayaman. These are located close to the contact of mapped diorite intrusions. Binit is developed in weathered argillic-altered siltstone with abundant hematite veins and malachite staining. Garnet and wollastonite skarn rocks have been reported (JICA, 2002) but the mineralization that is currently being mined by artisanal miners is hosted by quartz veins and hematite-filled fault zones. The B1 mine is developed in strong hematite and manganese-altered breccia near the diorite margin. Samples from both are reported to be anomalous in Au, Cu, Ag, As, Fe and Mn (Sierra Mining, unpublished data).
The Venida artisanal mine is within the Mabilo Property. Magnetite mineralization with significant associated copper-gold-silver occurs in a garnet-magnetite skarn zone. The garnet-magnetite zone grades through garnet skarn to wollastonite skarn developed in hornfelsed andesite, both of which are anomalous in copper and gold. The garnet and wollastonite skarn rocks are anomalous but low grade whereas the garnet-magnetite skarn is highly mineralized.
Mineralized magnetite skarn and massive garnet skarn preferentially replaced a cleaner limestone or marble horizon within the stratigraphic sequence. Drilling indicates that the main mineralized skarn zone dips to the southwest at 50 to 60 degrees in both the SMZ and NMZ. The NMZ was previously interpreted to be shallow dipping or north dipping, but additional drilling shows that when the skarn, marble, and breccias in marble are treated as single unit, it dips southwest. Where not eroded, the drilled mineralized zone is estimated to have a true thickness from 20 m in the south of the SMZ to over 80 m within a thicker marble / limestone unit in the NMZ.
The main magnetite zone mineralization typically comprises massive magnetite intergrown with minor retrograde-altered calc-silicate minerals (mainly garnet with subordinate wollastonite and
pyroxene), chalcopyrite and late interstitial calcite. Copper and gold grades are closely correlated and commonly reach 5% Cu and 5 g/t Au in hypogene mineralization. The copper-gold grade of magnetite skarn is variable but averages about 1.7% Cu and 1.9 g/t Au with 7 g/t Ag and 40% Fe. In the deep southeast part of the SMZ, hypogene bornite in magnetite skarn is associated with high copper and gold grades (up to 3-8% Cu and 3-24 g/t Au).
There are indications of zonation within the skarn in time and space, with probably early barren magnetite, strongly mineralized magnetite showing equilibrium textures with chalcopyrite, and later barren magnetite. Typically magnetite skarn is in direct replacive contact with marble at the downdip contact of the skarn zone without any zonation. Locally however, magnetite skarn grades down-dip into garnet skarn. More typically, garnet skarn occurs stratigraphically above or below magnetite skarn and shows zonation from red to green garnet, with variable copper-gold mineralization which can be of significant grade. In the SMZ, a separate mineralized garnet skarn horizon occurs in the stratigraphic hangingwall of the main magnetite skarn.